Differences Between Different Fiber Optical Connector II


4. ST Connector

The ST fiber optical connector was developed shortly after the arrival of the FC. At a glance, they can be mistaken for one another, but the ST uses a bayonet fitment rather than a screw thread. Usage has declined in recent decades, for the same reasons as the FC. Additionally, it cannot be terminated with an angled polish, which limits use in single mode fiber and FTTH applications.

Deployed predominately in multi-mode datacoms, it is most common in network environments such as campuses, corporate networks and in military applications where the quick connecting bayonet had its advantages at the time. It is typically installed into infrastructures that were built at the turn of the century. When retro-fitting, STs are typically swapped out for more cost effective SC and LC connectors.

5. MTP/MPO connector

The MT ferrule connector is another of NTT’s inventions and has been around since the 1980s, although the technology has only recently become popular under branded versions of the Multiple Fiber Push-On/Pull-Off connector, such as MTP and MPO. It is larger than the other finer optical connectors but for good reason, it can support up to 24 fibers in a single ferrule.

Multi-fiber connectors are not currently designed for field-fit applications, so they must be lab terminated. In high density patch environments, such as datacenters, they are used extensively, both at single mode and multi-mode wavelengths. On a ‘per-fiber’ basis, the costs are relatively inexpensive. However, as might be expected, the attenuation loss can be higher than a single ceramic ferrule connector. That being said, it is possible to order ‘low loss’ MTP/MPO connectors which have comparable insertion loss performances. These are more costly, however.

Network planners should also consider that whilst still using an adapter much like other connectors, the MTP/MPO must also be mated to an opposing male or female connector. This may require more than one connector specification or type within inventory, adding to cost and complexity.

Because the sequence of the fibers cannot physically be changed after termination, the fiber optical connector is often supplied with a fan-out assembly at the opposing end (such as LC, SC FC etc.). This allows the operator to change channels simply by re-patching the fanned-out side of the cable.

More common in datacoms, these fiber optical connectors are starting to appear in FTTH applications. They should therefore be considered if drivers include quick deployment of aggregate fibers, high density patching or where smaller ODFs and nodes might be crucial.

The differences between different types of Fiber Optical Connector can easily overlooked in the complex planning around fiber deployments. However, taking the time to select the right one for the job can deliver big benefits when it comes to speed and cost, so take the time to investigate your options before making your fiber optical connector choice.